Ballast device for nernst lamps.



PATENTED MAY 15, 1906.

L. GLASER. BALLAST DEVICE FOR NERNST LAMPS.

APPLICATION FILED JUNE 8.1905,

y w M Z U a N/ E6 y MM UNITED s'rnrns PANT oriuon BALLAST DEVEGE FQR NERNEET LAMPS.

Specification of Letters Patent.

Patented May 15, 1906.

Application filed June 8, 1905. Serial No. 264,263.

To all whom it may concern:

Be it known that I, LUDWIG. GLASER, a subject of the Duke of SaXe-Coburg-Gotha,

- residing at Berlin, Germany, have invented certain new and useful Improvements in Ballast Devices for Nernst Lamps, of which the following is a specification.

It has not heretofore been feasible to use second-class conductors of large cross-section for lamp-filaments because of the lack of a suitable ballast resistance. The iron wires which have proved successful as choking or reducing resistances for lamps with small iilaments do not begin to glow quick enough for filaments of larger cross-section. It is only possible to use these large filaments at high current by including in the circuit a regulating resistance; but this arrangement makes the lamps very expensive, especially as this regulating apparatus must be self-acting in order not to be dependent on the skill of the operator.

According to the followin invention it is possible to utilize with these arge glowers resis'tances made of iron wires or other suitable material with a high-temperature coeflicient,

rovided the resistance is divided into paralel parts only one of which is constantly connected to the glower and the other or others of which may be connected in parallel with the first at the proper time through any suit able automatic device. The resistances may be located in an evacuated vessel or in one filled with indifferent gas and so arranged that whenthe first resistance has heated the vessel to a suitable temperature the other resistance or resistances will be automatically put in circuit.

The accompanying drawing shows my im proved arrangement.

The supply-wires 1 and 2 conduct current through the bottom of the evacuated vessel and are connected, respectively, to the wires 3 and 4 within the vessel. Between 3 and 4 an iron wire 5 is wound in spiral form. A second wire 6 is connected from 4 to the short wire 7, which is fastened to a glass ball 8, melted to the wire 3 and serving to insulate the wire 7 from the Wire 3. A spiral spring 9, commonly known as a Breguetts spring, is carried on the wire 7 and is of such a nature that when heated sufiiciently it will touch the contact'wire 10, connected to 3, but when cool will interrupt this contact immediately. The wire 10 may be made of platinum, nickel, or other suitable material For operating a two-am ere lamp the dimensions of the wires 5 an 6 may be so proportioned that one carries 1.5 amperes and the other .5 amperes. When the lamp has been switched on and while the glower 11 is becoming more conductive, the current which goes through the glower will flow at first only through the resistance 5. This resistance will begin to glow immediately, as it is con structed for a weaker strength of current than the glower, and thus will delay for a short time any increase oi current above 1.5 am eres. in the meantime the whole vessel wil be heated from resistance 5, and the spring 9 will be turned to establish contact with the wire 10. This operation throws the resistance 6 in shunt with the resistance 5, thus raising the total current to two amperes. The resistance 6 when thrown in circuit is brought rapidly to a red heat and then begins to choke, as will be readily understood.

It is very important to prevent any sub stantial vibration of the spring 9, as the temperature at which the contact is established and also the time interval between the switching on of the lamp and the establishment of the multiple circuit should be always constant. For this reason a stop 12, of insulated wire, is arranged on the side of the sprin oppoi-ate the wire 10. By the distance 0 the two wires 10 and 12 the above-mentioned interval can be regulated. The regulation of the resistance may be effected by any of the well-known methods.

For electric lam s of very high current a suitabledivision o the resistances may be made when necessary, so that several iron wires are arranged in parallel, one of which is constantly switched on, but the others of which ma be switched on one after the other as neede through the instrumentality of a plurality of Breguetts springs of different sizes and having different movement-spaces.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. A ballast for second-class conductors comprising a resistance having a high-temperature coellicient, a second resistance operatively related thereto, and automatic means for connectin said second resistance in shunt'with said. first resistance after the latter has attained a suitable temperature.

2. A ballast device for a conductor of the second class including as a part thereof a resistance having a high-temperature coeiiicient, and automatic means for connecting two filaments in parallell 5. A ballast for conductors ofthe second class comprising an evacuated chainber, a h1gh--I6SlSi/&Il(36 hlamenttherein, 'means for ballast device for a conductor of the supplying current thereto second filament therein, and automatic means in said chamber :for' 'comiect ing said filaments in parallel after one of said filaments has been heated by the flow of current threthrough.

6. A ballast for electric apparatus comprising an evacuated chamber, a highresist ance filament therein, a second. resistance operatively related thereto, and a heat-actuated spiral for connecting said resistances in parallel when said chamber has reached a predetermined temperature.

In Witness whereof I have hereunto set my hand this 22d day of May, 1905.

LUDVVIG GLASER.

Witnesses: a

JULIUS R'UMLAND,

-. KARL GL LiEKEBEN. 

